Because Opera is not an extremely popular browser, most developers probably aren’t aware of one of its greatest features: Opera Show mode. Opera Show mode is the official name of the full screen mode for Opera (technically, it’s only called Opera Show when a projection media style sheet – discussed below – is present); and it brings with it a great possibility.

More than two years ago, Opera added support for the projection media mode in CSS. Whenever the browser is expanded to full screen mode, it activates the projection media, allowing you to apply a completely different stylesheet to the full screen page than you have in other settings.